Orthogonal frequency division multiplexing with index modulation (OFDM-IM) [1]} is an emerging technique which is the application of the spatial modulation (SM) [2]} principle to the subcarriers in an OFDM system. In OFDM-IM, the subcarriers are partitioned into many subblocks and, in each subblock, the subcarriers have two states, active or idle. Then, OFDM-IM conveys information through not only modulated symbols but also the indices of the active subcarriers. For the same spectral efficiency, OFDM-IM is shown to have a superior bit error rate (BER) performance when compared to the classical OFDM [1]}. Also, OFDM-IM systems have a better energy efficiency compared to the classical OFDM [4]}.
